You may recall that back in May, we spotted something in Google’s “Dear Sophie” commercial: an unreleased +1 Chrome extension. This was pre-Google+, when the +1 button still didn’t do a whole lot, so even I forgot about the extension over the past few months. But very quietly, Google actually launched it yesterday.

There was no blog post, no featured placement in the Chrome Web Store — pretty much no fanfare beyond Google SVP of Chrome, Sundar Pichai, posting a link to it on Google+. But it has the potential to be a bigger deal than it seems on the surface.As the tagline indicates, the Google +1 Button extension allows you to “+1 a web page, anywhere you go on the web”. That’s important. You no longer have to rely on a site to implement the +1 Button, you can invoke the functionality through your browser. Imagine if Facebook made their own browser and offered an extension to “Like” any page on the web through it — same idea (and one that I still suspect will happen sooner or later).Right now, the +1 Button just shares content you like on the web. But eventually, the plan is to look at this data as a way to affect Google Search itself potentially. That’s huge. The button also is starting to play a role in how Google serves up advertising to you. Again, huge — though these concepts may make people wary of such a button.As Google notes in their description of the app:

In addition to the practices described in the Google +1 Button Privacy Policy, by installing this extension, all of the pages and URLs you visit will be sent to Google in order to retrieve +1 information.

Yes, you read that correctly, “all of the pages and URLs you visit will be sent to Google” — and that’s even if you don’t click the button. Nefarious or not, that will worry some people.And while the +1 Buttons for websites just added the functionality to share your Google+ Circles, the extension doesn’t yet offer that — but I assume it will. It does offer +1 counts though already, which is nice.Find the extension here. Again, it’s Chrome only for now, we’ll see if they create ones for Firefox, IE, and Safari as well.Update: For those concerned about privacy, Google pointed me to this page: How the +1 button respects your privacy.